Many of today's highly integrated products have become exceedingly popular. These products include cell phones that include a camera, or a global positioning system that includes an audio player for personal music downloads. In order to integrate these diverse functions quickly, the electronics industry has pushed the boundaries of package technology in many directions.
Integrated circuit dice are conventionally enclosed in plastic packages that provide protection from hostile environments and enable electrical interconnection between the integrated circuit die and an underlying substrate such as a printed circuit board (PCB). The elements of such a package include a conductive lead frame, an integrated circuit die, bonding material to attach the integrated circuit die to the lead frame, bond wires which electrically connect pads on the integrated circuit die to individual leads of the lead frame, and a hard plastic encapsulant material which covers the other components and forms the exterior of the package.
The lead frame is the central supporting structure of such a package. A portion of the lead frame is internal to the package, i.e., completely surrounded by the plastic encapsulant. Portions of the leads of the lead frame extend externally from the package or are partially exposed within the encapsulant material for use in electrically connecting the package to another component. In certain semiconductor packages, a portion of the die pad of the lead frame also remains exposed within the exterior of the package for use as a heat sink.
One type of semiconductor package commonly known in the electronics field is referred to as a quad flat pack (QFP) package. A typical QFP package comprises a thin, generally square package body defining four peripheral sides of substantially equal length. Protruding from each of the four peripheral sides of the package body are a number of leads which each have a generally gull-wing configuration. Portions of the leads are internal to the package body, and are electrically connected to respective ones of the pads or terminals of a semiconductor die also encapsulated within the package body. The semiconductor die is itself mounted to a die pad of the QFP package lead frame.
There is a current need in the electronics industry for a QFP package which includes additional input/output capabilities than can be provided by the leads protruding from the sides of the package body. Thus, a need still remains for an integrated circuit packaging system with increased connectivity that can provide additional connection options for highly integrated electronic packages while maintaining a thin profile. In view of the rapid development of products that require high levels of integration, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to save costs, improve efficiencies and performance, and meet competitive pressures, adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.